U.S. patent number 10,177,294 [Application Number 15/297,944] was granted by the patent office on 2019-01-08 for illumination apparatus.
This patent grant is currently assigned to LG INNOTEK CO., LTD.. The grantee listed for this patent is LG INNOTEK CO., LTD.. Invention is credited to Do Yub Kim, Min Hak Kim, Myung Jin Song.
United States Patent |
10,177,294 |
Kim , et al. |
January 8, 2019 |
Illumination apparatus
Abstract
Embodiments provide an illumination apparatus including a light
emitting module including a board, at least one light emitting
device disposed in a first region of the board and drive devices
disposed in a second region of the board, a heat dissipation
member, and dummy pads disposed around the at least one light
emitting device, the heat dissipation member including a base, a
core, and heat dissipation fins connected to the side surface of
the core and the lower surface of the base. The first region is one
region of the upper surface of the board, located within a
designated range from the center of the board, and the second
region is another region of the upper surface of the board, spaced
apart from the first region by a first distance and spaced apart
from the edge of the upper surface of the board by a second
distance.
Inventors: |
Kim; Min Hak (Seoul,
KR), Kim; Do Yub (Seoul, KR), Song; Myung
Jin (Seoul, KR) |
Applicant: |
Name |
City |
State |
Country |
Type |
LG INNOTEK CO., LTD. |
Seoul |
N/A |
KR |
|
|
Assignee: |
LG INNOTEK CO., LTD. (Seoul,
KR)
|
Family
ID: |
57240809 |
Appl.
No.: |
15/297,944 |
Filed: |
October 19, 2016 |
Prior Publication Data
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|
|
|
Document
Identifier |
Publication Date |
|
US 20170110640 A1 |
Apr 20, 2017 |
|
Foreign Application Priority Data
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|
|
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Oct 20, 2015 [KR] |
|
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10-2015-0145893 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F21V
29/503 (20150115); H01L 33/483 (20130101); H01L
33/62 (20130101); F21V 21/0832 (20130101); F21V
29/773 (20150115); H01L 33/60 (20130101); H01L
33/644 (20130101); F21S 8/06 (20130101); F21V
15/01 (20130101); F21S 8/026 (20130101); F21V
23/005 (20130101); H05K 2201/09781 (20130101); H05K
2201/066 (20130101); H05K 1/0209 (20130101); F21Y
2115/10 (20160801); H05K 2201/10106 (20130101) |
Current International
Class: |
F21S
8/02 (20060101); F21V 29/77 (20150101); F21V
29/503 (20150101); F21V 21/08 (20060101); H01L
33/64 (20100101); H01L 33/48 (20100101); F21V
23/00 (20150101); F21V 15/01 (20060101); H01L
33/62 (20100101); H01L 33/60 (20100101); F21S
8/06 (20060101); H05K 1/02 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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10 2010 002 235 |
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Aug 2011 |
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DE |
|
2 086 294 |
|
Aug 2009 |
|
EP |
|
2 244 001 |
|
Oct 2010 |
|
EP |
|
2009-218204 |
|
Sep 2009 |
|
JP |
|
2012-54181 |
|
Mar 2012 |
|
JP |
|
2012-69487 |
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Apr 2012 |
|
JP |
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WO 2012/168831 |
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Dec 2012 |
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WO |
|
Primary Examiner: Santiago; Mariceli
Attorney, Agent or Firm: Birch, Stewart, Kolasch &
Birch, LLP
Claims
What is claimed is:
1. An illumination apparatus comprising: a light emitting module
including a board, a plurality of light emitting devices disposed
in a first region of the board, and drive devices disposed in a
second region of the board so as to drive the plurality of light
emitting devices; a heat dissipation member disposed on a lower
surface of the board; and dummy pads disposed in the first region
of the board around the plurality of light emitting devices,
wherein the heat dissipation member includes: a base corresponding
to the lower surface of the board; a core connected to a lower
surface of the base; and heat dissipation fins connected to a side
surface of the core and the lower surface of the base, wherein the
first region is one region of an upper surface of the board
corresponding to the core, including a center of the upper surface
of the board and located within a designated range from the center
of the upper surface of the board, and the second region is another
region of the upper surface of the board, spaced apart from the
first region by a first distance and spaced apart from an edge of
the upper surface of the board by a second distance, wherein a
diameter of the core is equal to or greater than a diameter of the
first region, and wherein the dummy pads are disposed in a portion
of the first region corresponding to the core.
2. The illumination apparatus according to claim 1, wherein the
dummy pads surround outermost light emitting devices out of the
plurality of light emitting devices.
3. The illumination apparatus according to claim 2, wherein the
dummy pads are disposed both in the first region of the board and
in a region located between the first region and the second region
of the board.
4. The illumination apparatus according to claim 2, wherein a
distance between the dummy pads and the second region of the board
is 14 mm or more.
5. The illumination apparatus according to claim 2, wherein the
first distance is greater than the second distance.
6. The illumination apparatus according to claim 2, wherein an area
of each of the dummy pads is greater than an area of a light
emitting surface of each of the plurality of light emitting
devices.
7. The illumination apparatus according to claim 2, wherein: the
board includes pads to dispose the plurality of light emitting
devices thereon; and the dummy pads contact the pads.
8. The illumination apparatus according to claim 2, wherein: the
board includes pads to dispose the plurality of light emitting
devices thereon; and the dummy pads are separated from the
pads.
9. The illumination apparatus according to claim 1, wherein a ratio
of a diameter of the core to a diameter of the first region of the
board is 5/6 to 4/3.
10. The illumination apparatus according to claim 1, further
comprising: a heat dissipation pad disposed between the lower
surface of the board and the base of the heat dissipation member;
and a housing configured to receive the light emitting module and
the heat dissipation pad.
11. The illumination apparatus according to claim 10, wherein the
housing includes a first opening corresponding to the first region
of the board, a second opening configured to emit light generated
from the plurality of light emitting devices, and a reflective part
including a reflective surface located between the first opening
and the second opening, and wherein the reflective surface is
located between the drive devices and the plurality of light
emitting devices.
12. The illumination apparatus according to claim 11, further
comprising a diffusion plate disposed on the second opening.
13. The illumination apparatus according to claim 10, wherein: an
upper surface of the base includes a first region corresponding to
the board such that the board is disposed thereon, and a second
region configured to surround the first region; through holes
provided in the second region of the base; and coupling members
passing through the through holes and combined with a lower end of
the housing.
14. The illumination apparatus according to claim 1, wherein a
center of the core is aligned with a center of the first region of
the board.
15. The illumination apparatus according to claim 14, wherein the
center of the core is aligned with a center of the base.
16. The illumination apparatus according to claim 1, wherein one
end of each of the heat dissipation fins is connected to the side
surface of the core, and the other end of each of the heat
dissipation fins extends to an edge of the lower surface of the
base.
17. The illumination apparatus according to claim 16, wherein a
thickness of the core is greater than a thickness of the base.
18. The illumination apparatus according to claim 1, wherein the
dummy pads are disposed between the plurality of light emitting
devices disposed at an outermost area of the first region and an
outermost line of the first region, and wherein the second region
has a circular ring shape with a predetermined width and
surrounding the first region.
19. An illumination apparatus comprising: a light emitting module
including a board, light emitting devices disposed in a first
region of the board, drive devices disposed in a second region of
the board so as to drive the light emitting devices, and dummy pads
disposed in the first region of the board between the light
emitting devices and the drive devices; a heat dissipation member
including a base provided with an upper surface contacting a lower
surface of the board, a core connected to a lower surface of the
base, and heat dissipation fins connected to a side surface of the
core and the lower surface of the base; a heat dissipation pad
disposed between the lower surface of the board and the base; and a
housing configured to receive the light emitting module and the
heat dissipation pad, wherein: the dummy pads surround outermost
light emitting devices out of the light emitting devices; and the
first region is one region of the upper surface of the board
corresponding to the core, including the center of the upper
surface of the board and located within a designated range from the
center of the board, and the second region is another region of the
upper surface of the board, spaced apart from the first region and
an edge of the upper surface of the board, wherein a diameter of
the core is equal to or greater than a diameter of the first
region, and wherein the dummy pads are disposed in a portion of the
first region corresponding to the core.
20. The illumination apparatus according to claim 19, wherein the
dummy pads are disposed between the plurality of light emitting
devices disposed at an outermost area of the first region and an
outermost line of the first region, and wherein the second region
has a circular ring shape with a predetermined width and
surrounding the first region.
Description
CROSS REFERENCE TO RELATED APPLICATION
This application claims priority under 35 U.S.C. .sctn. 119 to
Korean Patent Application No. 10-2015-0145893, filed in Korea on
Oct. 20, 2015, which is hereby incorporated in its entirety by
reference as if fully set forth herein.
TECHNICAL FIELD
Embodiments relate to an illumination apparatus.
BACKGROUND
In general, an illumination apparatus including an LED light
emitting module driven by AC may include a plurality of LEDs
disposed on a substrate and at least one drive device (for example,
a driver IC, a bridge diode and a condenser) disposed adjacent to
the LEDs.
A light source of the LED light emitting module may be a package
type and, in this case, heat dissipation efficiency may be poor and
costs may be increased. Further, the drive devices disposed
adjacent to the LEDs absorb light and thus light loss may
occur.
Further, heat generated from the LEDs may thermally damage the
drive devices disposed adjacent to the LEDs.
SUMMARY
Embodiments provide an illumination apparatus which may prevent
lifetime of drive devices from being shortened due to heat
generated from light emitting devices.
In one embodiment, an illumination apparatus includes a light
emitting module including a board, at least one light emitting
device disposed in a first region of the board, and drive devices
disposed in a second region of the board so as to drive the at
least one light emitting device, a heat dissipation member disposed
on a lower surface of the board, and dummy pads disposed in a
region of the board around the at least one light emitting device,
wherein the heat dissipation member includes a base corresponding
to the lower surface of the board, a core connected to a lower
surface of the base, and heat dissipation fins connected to a side
surface of the core and the lower surface of the base, wherein the
first region is one region of an upper surface of the board,
including a center of the upper surface of the board and located
within a designated range from the center of the upper surface of
the board, and the second region is another region of the upper
surface of the board, spaced apart from the first region by a first
distance and spaced apart from an edge of the upper surface of the
board by a second distance.
The at least one light emitting device may include a plurality of
light emitting devices, and the dummy pads may surround outermost
light emitting devices out of the light emitting devices.
The dummy pads may be disposed in the first region of the
board.
The dummy pads may be disposed both in the first region of the
board and in a region located between the first region and the
second region of the board.
A distance between the dummy pads and the second region of the
board may be 14 mm or more.
The first distance may be greater than the second distance.
An area of each of the dummy pads may be greater than an area of a
light emitting surface of each of the light emitting devices.
A ratio of a diameter of the core to a diameter of the first region
of the board may be 5/6 to 4/3.
The illumination may further include a heat dissipation pad
disposed between the lower surface of the board and the base of the
heat dissipation member and a housing configured to receive the
light emitting module and the heat dissipation pad.
The housing may include a first opening corresponding to the first
region of the board, a second opening configured to emit light
generated from the at least one light emitting device, and a
reflective part including a reflective surface located between the
first opening and the second opening, and the reflective surface
may be located between the drive devices and the at least one light
emitting device.
The illumination apparatus may further include a diffusion plate
disposed on the second opening.
A center of the core may be aligned with the center of the first
region of the board.
The board may include pads to dispose the light emitting devices
thereon, and the dummy pads may contact the pads.
The board may include pads to dispose the light emitting devices
thereon, and the dummy pads may be separated from the pads.
The upper surface of the base may include a first region
corresponding to the board such that the board is disposed thereon
and a second region configured to surround the first region,
through holes may be provided in the second region of the base, and
coupling members may pass through the through holes and be combined
with the lower end of the housing.
One end of each of the heat dissipation fins may be connected to
the side surface of the core, and the other end of each of the heat
dissipation fins may extend to an edge of the lower surface of the
base.
A thickness of the core may be greater than a thickness of the
base.
The center of the core may be aligned with the center of the
base.
In another embodiment, an illumination apparatus includes a light
emitting module including a board, light emitting devices disposed
in a first region of the board, drive devices disposed in a second
region of the board so as to drive the light emitting devices, and
dummy pads disposed on an upper surface of the board between the
light emitting devices and the drive devices, and a heat
dissipation member including a base provided with an upper surface
contacting a lower surface of the board, a core connected to a
lower surface of the base, and heat dissipation fins connected to
the side surface of the core and a lower surface of the base,
wherein the first region is one region of the upper surface of the
board, including a center of the upper surface of the board and
located within a designated range from the center of the upper
surface of the board, and the second region is another region of
the upper surface of the board, spaced apart from the first region
and an edge of the upper surface of the board.
In yet another embodiment, an illumination apparatus includes a
light emitting module including a board, light emitting devices
disposed in a first region of the board, drive devices disposed in
a second region of the board so as to drive the light emitting
devices, and dummy pads disposed on an upper surface of the board
between the light emitting devices and the drive devices, a heat
dissipation member including a base provided with an upper surface
contacting the lower surface of the board, a core connected to the
lower surface of the base, and heat dissipation fins connected to a
side surface of the core and a lower surface of the base, a heat
dissipation pad disposed between a lower surface of the board and
the base, and a housing configured to receive the light emitting
module and the heat dissipation pad, wherein the dummy pads
surround outermost light emitting devices out of the light emitting
devices, the first region is one region of the upper surface of the
board, including the center of the upper surface of the board and
located within a designated range from the center of the board, and
the second region is another region of the upper surface of the
board, spaced apart from the first region and an edge of the upper
surface of the board.
BRIEF DESCRIPTION OF THE DRAWINGS
Arrangements and embodiments may be described in detail with
reference to the following drawings in which like reference
numerals refer to like elements and wherein:
FIG. 1 is an exploded perspective view of an illumination apparatus
in accordance with one embodiment;
FIG. 2 is a first assembled perspective view of the illumination
apparatus shown in FIG. 1;
FIG. 3 is a second assembled perspective view of the illumination
apparatus shown in FIG. 1;
FIG. 4 is a cross-sectional view of the illumination apparatus
shown in FIG. 2, taken along line A-B;
FIG. 5A is a perspective view of a light emitting module shown in
FIG. 1 in accordance with one embodiment;
FIG. 5B is a view illustrating regions in which at least one light
emitting device and drive devices shown in FIG. 5A are located;
FIG. 6 is a first perspective view of a heat dissipation member
shown in FIG. 1;
FIG. 7 is a second perspective view of the heat dissipation member
shown in FIG. 1;
FIG. 8 is a cross-sectional view of the heat dissipation member
shown in FIG. 6, taken along line C-D;
FIG. 9 is a perspective view of a light emitting module in
accordance with another embodiment;
FIG. 10 is a table representing simulation results and test results
indicating temperatures of light emitting devices, temperatures of
condensers and temperature differences between the light emitting
devices and the condensers according to change of diameters of
cores;
FIG. 11 is a table representing test results of Case 4 of FIG. 10;
and
FIG. 12 is a table representing test results of Case 6 of FIG.
10.
DESCRIPTION OF SPECIFIC EMBODIMENTS
Hereinafter, embodiments will be described with reference to the
annexed drawings. In the following description of the embodiments,
it will be understood that, when each element, such as a layer
(film), a region, a pattern or a structure, is referred to as being
"on" or "under" another element, such as a substrate, a layer
(film), region, a pattern or a pad, it can be directly "on" or
"under" the other element or be indirectly formed with one or more
intervening elements therebetween. In addition, it will also be
understood that a criteria to determine an upward direction and a
downward direction of one element is judged based on the
drawings.
In the drawings, thicknesses or sizes of respective layers may be
exaggerated, omitted, or schematically illustrated for convenience
and clarity of description. Further, the sizes of respective
elements do not indicate actual sizes thereof. In the drawings, the
same or similar elements are denoted by the same reference numerals
even though they are depicted in different drawings.
FIG. 1 is an exploded perspective view of an illumination apparatus
100 in accordance with one embodiment, FIG. 2 is a first assembled
perspective view of the illumination apparatus 100 shown in FIG. 1,
FIG. 3 is a second assembled perspective view of the illumination
apparatus 100 shown in FIG. 1, and FIG. 4 is a cross-sectional view
of the illumination apparatus 100 shown in FIG. 2, taken along line
A-B.
With reference to FIGS. 1 to 4, an illumination apparatus 100
includes a light emitting module 110, a heat dissipation member
120, a housing 130, and a diffusion plate 140.
The light emitting module 110 emits light.
FIG. 5A is a perspective view of the light emitting module 110
shown in FIG. 1 in accordance with one embodiment. With reference
to FIG. 5A, the light emitting module 110 may include a board 12,
at least one light emitting device 114, and drive devices 116.
The board 112 may be formed of a material, such as silicon, a
synthetic resin or a metal.
For example, the board 112 may be formed of a conductive material
which greatly dissipates heat, such as Al, and, in order to prevent
electrical short-circuit between the at least one light emitting
device 114 and the drive devices 116, the surface of the board 112
may be coated with an insulating layer (not shown).
Further, for example, the board 112 may include a printed circuit
board which may conductibly connect the at least one light emitting
device 114 and the drive devices 116.
For example, the board 112 may be a printed circuit board including
an FR4 or CEM-1 PCB.
The at least one light emitting device 114 and the drive devices
116 are disposed on an upper surface 112a of the board 112.
For example, the at least one light emitting device 114 may be a
light emitting diode which emits light, and be formed as a chip
type or a package type.
FIG. 5B is a view illustrating regions 112a and 112b in which the
at least one light emitting device 114 and the drive devices 116
shown in FIG. 5A are located.
With reference to FIG. 5B, the upper surface 112a of the board 112
may include first and second regions 112a and 112b.
The at least one light emitting device 114 may be disposed in the
first region 112a of the board 112, and the drive devices 116 may
be disposed in the second region 112b of the board 112.
The first region 112a of the board 112 may be a central region of
the upper surface 112a of the board 112, including the center 101
of the board 112 and located within a designated range from the
center 101 of the board 112. For example, the first region 112a of
the board 112 may have a circular shape, an oval shape or a
polygonal shape.
The second region 112b of the board 112 may be spaced apart from
the first region 112a of the board 112 by a first distance d1 and
be spaced from the edge of the upper surface 112a of the board 112
by a second distance d2. For example, the second region 112b of the
board 112 may have a ring shape or a circular, oval or polygonal
band shape, but the disclosure is not limited thereto.
For example, the second region 112b of the board 112 may have a
circular ring shape with a designated width.
For example, in consideration of the number of light emitting
devices disposed in the first regions 112a, the diameter D1 of the
first region 112a of the board 112 may be 25 mm to 35 mm. For
example, the diameter D1 of the first region 112a of the board 112
may be 30 mm.
For example, the width W1 of the second region 112b of the board
112 may be 15 mm to 20 mm.
For example, the width W1 of the second region 112b of the board
112 may be 17.5 mm.
The diameter D1 of the first region 112a of the board 112 may be
greater than the width W1 of the second region 112b of the board
112 (D1>W1).
The first distance d1 may be greater than the second distance d2
(d1>d2). The reason for this is to elongate a transmission path
of heat generated from the at least one light emitting device 114
to the drive devices 116 by increasing the distance d1 between the
drive devices 116 and the at least one light emitting device 114
and thus to suppress rise of the temperature of the drive devices
116 to improve lifetime of the drive devices 116.
The first distance d1 may be 10 mm to 15 mm. For example, the first
distance d1 may be 12 mm.
The second distance d2 may be 3 mm to 7 mm. For example, the second
distance d2 may be 5 mm.
The at least one light emitting device 114 may be a plurality of
light emitting devices 114. If a plurality of light emitting
devices 114 is provided, the light emitting devices 114-1 to 114-n
(n being a natural number of greater than 1; n>1), which are
spaced apart from each other, may be disposed in the first region
112a of the board 112.
The light emitting devices 114-1 to 114-n may be connected in
series, but the disclosure is not limited thereto. In other
embodiments, the light emitting devices 114-1 to 114-n may be
connected in parallel or connected in serial-parallel.
The drive devices 116 may drive the light emitting devices 114-1 to
114-n using AC power. For example, the drive devices 116 may
rectify the AC power, convert the AC power into DC power, and
provide the DC power to the light emitting devices 114-1 to
114-n.
For example, the drive devices 116 may include a power supply unit
to provide direct current to the light emitting devices 114-1 to
114-n.
For example, the drive devices 116 may include a bridge diode
116-1, a voltage converter 116-2, condensers 116-3, a driver IC
116-4, a Zener diode 116-5, resistors 116-6a and 116-6b, etc.
Further, the drive devices 116 may further include an inductor, an
output diode, and an FET 116-7.
The bridge diode 116-1 rectifies AC power.
The condensers 116-3 and the resistors 116-6a and 116-6b may
constitute a smoothing circuit and convert the rectified AC power
into DC power.
The voltage converter 116-2 converts voltage of the DC power of the
smoothing circuit so as to match operating voltage of the at least
one light emitting device 114. The driver IC 116-4 may control
operation of the at least one light emitting device 114. The Zener
diode 116-5 may protect the at least one light emitting device 114
and the drive devices 116 from surge introduced from the
outside.
The heat dissipation member 120 is disposed on the lower surface of
the board 112 of the light emitting module 110 and dissipates heat
generated from the at least one light emitting device 114.
FIG. 6 is a first perspective view of a heat dissipation member 120
shown in FIG. 1, FIG. 7 is a second perspective view of the heat
dissipation member 120 shown in FIG. 1, and FIG. 8 is a
cross-sectional view of the heat dissipation member 120 shown in
FIG. 6, taken along line C-D.
With reference to FIGS. 6 to 8, the heat dissipation member 120 may
include a base 122a, a core 122b, and heat dissipation fins
122c.
The base 122a may have a plate shape corresponding to the board 112
and be formed of a metal having high thermal conductivity, for
example, aluminum (Al). For example, the base 122a may have a shape
coinciding with the shape of the board 112 and have a uniform
thickness. For example, the base 122a may have a circular shape, an
oval shape or a polygonal shape, but the disclosure is not limited
thereto.
An upper surface 122a1 of the base 122a is located opposite the
lower surface of the board 112, and the upper surface 122a1 of the
base 122a and the lower surface of the board 112 may contact each
other. The board 112 of the light emitting module 110 may be
disposed on the upper surface 122a1 of the base 122a. Through holes
201, through which coupling members 170 for coupling with the
housing 130 pass, may be formed through the base 122a. The coupling
members 170 may pass through the through holes 201 and be coupled
with the lower end of a first part 130A of the housing 130.
For example, the upper surface 122a1 of the base 122a may include a
first region 122-1 corresponding to the board 112 such that the
board 112 is seated or disposed in the first region 122-1, and a
second region 122-2 formed at the edge of the upper surface 122a1
so as to surround the first region 122-1.
For example, the number of the through holes 201 may be more than
2, and 2 or more through holes 201 may be disposed in the second
region 122-2 of the base 122a so as to be spaced apart from each
other. As exemplarily shown in FIG. 7, the through holes 201 may be
located between the heat dissipation fins 122c or be aligned
between the heat dissipation fins 122c.
If the through holes 201 are disposed in the first region 122-1 of
the base 122a, a contact area between the upper surface 122a of the
base 122a and the lower surface of the board 112 is reduced and
thus heat dissipation efficiency may be lowered. Therefore, in
accordance with this embodiment, the through holes 201 are disposed
in the second region 122-2 of the base 122a and thus heat
dissipation efficiency may be improved.
The core 122b is connected to a rear or lower surface 122a2 of the
base 122a and is located so as to correspond to or to be aligned
with the first region 112a of the board 112. Heat generated from
the light emitting devices 114-1 to 114-n located in the first
region 112a is dissipated through the core 122b, thus improving
heat dissipation efficiency. The core 122b may mean a core part for
heat dissipation and "core" may be replaced with other terms such
as heat sink, heat dissipation part, heat dissipation central part,
protruding part, or core part.
For example, a center 301 of the core 122b may be aligned with a
center 401 of the base 122a. Further, for example, the center 301
of the core 122b may be aligned with a center 101 of the first
region 112a of the board 112. Thereby, an overlap area of the first
region 112a of the board 112 with the core 122b may be increased
and, in this embodiment, light dissipation efficiency may be
improved.
The heat dissipation fins 122c may be connected to a side surface
122b1 of the core 122b and the lower surface 122a2 of the base
122a, and dissipate heat transmitted from the core 122b.
Since the heat dissipation fins 122c contact both the side surface
122b1 of the core 122b and the lower surface 122a2 of the base
122a, in this embodiment, a contact area of the heat dissipation
fins 122c with the base 122a and the core 122b is increased and
thus heat dissipation efficiency may be increased.
For example, the heat dissipation fins 122c may have a plate shape,
be provided in plural, and be arranged in a radial shape about the
core 122b.
One end of each of a plurality of heat dissipation fins 122c may be
connected to the side surface 122b1 of the core 122b, and the upper
surfaces of the heat dissipation fins 122c may be connected to the
lower surface 122a2 of the base 122c.
The other ends of the heat dissipation fins 122c may extend to the
edge of the lower surface 122a2 of the base 122a and contact the
edge of the lower surface 122a2 of the base 122a. Therefore, in
this embodiment, a contact area between the heat dissipation fins
122c and the base 122a is increased and thus heat dissipation
efficiency may be increased.
In order to improve heat dissipation efficiency, the thickness T1
of the core 122b is greater than the thickness T2 of the base 122a.
Here, the thickness T1 of the core 122b may be a distance from the
upper end of the core 122b connected to the lower surface 122a2 of
the base 122a to the lower end of the core 122b.
Since the core 122b is aligned with the first region 112a of the
board 112 in which the light emitting devices 114-1 to 114-n are
located and the thickness T1 of the core 122b is greater than the
thickness T2 of the base 112a, heat generated from the light
emitting devices 114-1 to 114-n may be effectively transmitted to
the heat dissipation fins 122c through the core 122b and thus heat
dissipation efficiency may be improved. For example, the thickness
T1 of the core 122b may be twice or more the thickness T2 of the
base 112 (T1.ltoreq.2.times.T2).
The illumination apparatus 100 may further include a heat
dissipation pad 160 disposed between the board 112 of the light
emitting module 110 and the heat dissipation member 120. The heat
dissipation pad 160 may be an insulating member which may improve
heat transfer from the light emitting devices 114 to the heat
dissipation member 120.
The housing 130 may include a first part 130A connected to the heat
dissipation member 120 and receiving the light emitting module 110
and the heat dissipation pad 160, and a second part 130B connected
to one end of the first part 130A and including a protrusion
protruding in the side direction. The housing 130 may be formed of
a metal or plastic.
The first part 130A of the housing 130 may include a first opening
131, a second opening 132, and a reflective part 130a including a
reflective surface 133 between the first opening 131 and the second
opening 132.
The first opening 131 may be provided at one end of the reflective
surface 133, correspond to or be aligned with the first region 112a
of the board 112, and expose the light emitting devices 114-1 to
114-n.
The reflective surface 133 of the housing 130 may reflect light
irradiated from the light emitting devices 114-1 to 114-n. The
reflective surface 133 may be inclined at a designated angle from
the upper surface of the board 112.
The second opening 132 of the housing 130 is provided at the other
end of the reflective surface 133. The diameter of the second
opening 132 may be greater than the diameter of the first opening
131, but the disclosure is not limited thereto. For example, the
reflective surface 133 of the housing 130 may have a circular
truncated conical shape, but the disclosure is not limited
thereto.
A vacant space may be provided between the side part and the
reflective part 130a of the housing 130, and the drive devices 116
may be disposed between an inner surface 138 of the side part of
the housing 130 and the outer surface of the reflective part
130a.
Since the reflective surface 133 of the reflective part 130a are
located between the drive devices 116 and the light emitting
devices 114-1 to 114-n and the reflective surface 133 reflects
light irradiated from the light emitting devices 114-1 to 114-n,
the reflective part 130a may prevent the drive devices 116 from
absorbing light and luminous efficiency of the illumination
apparatus 100 may be improved.
The diffusion plate 140 may be disposed on the housing 140 and
diffuses light irradiated from the light emitting devices 114-1 to
114-n. For example, the diffusion plate 140 may be disposed so as
to cover the second opening 132 of the housing 130.
The illumination apparatus 100 may further include a diffusion
plate fixing part 145 to fix the diffusion plate 140 to the housing
130.
The illumination apparatus 100 may further include support parts
152 and 154 combined with the housing 130 to support the housing
130.
For example, the support parts 152 and 154 may be combined with the
outer surface of the side part of the housing 130 by coupling
members, such as screws. The support parts 152 and 154 may have a
wire shape, without being limited thereto, and both ends of the
support parts 152 and 154 may be bent to form a hook to be hung on
protrusions. Here, the protrusions may be provided in a place or an
object, in or to which the illumination apparatus 100 is installed
or fixed.
FIG. 9 is a perspective view of a light emitting module 110-1 in
accordance with another embodiment. Some parts in this embodiment,
which are substantially the same as those in the embodiment shown
in FIG. 5A, are denoted by the same reference numerals even though
they are depicted in different drawings, and a detailed description
thereof will thus be omitted because it is considered to be
unnecessary.
With reference to FIG. 9, the light emitting module 110-1 may
include light emitting devices 114-1 to 114-n (n being a natural
number of greater than 1; n>1), dummy pads 119-1 to 119-6, and
drive devices 116.
The dummy pads 119-1 to 119-6 may be disposed in one region of a
board 112, which is located between the light emitting devices
114-1 to 114-n and the drive devices 116.
The dummy pads 119-1 to 119-6 are disposed in a first region 112a
of the board 112 around the light emitting devices 114-1 to 114-n,
and serve to suppress transfer of heat generated from the light
emitting devices 114-1 to 114-n to the drive devices 116.
For example, as exemplarily shown in FIG. 9, the dummy pads 119-1
to 119-6 may be disposed between the light emitting devices 114-1
to 114-n disposed at the outermost area of the first region 112a
and an outermost line 112a-1 (with reference to FIG. 5B) of the
first region 112a.
Since the dummy pads 119-1 to 119-6 are disposed adjacent to the
light emitting devices 114-1 to 114-n, transfer of heat to the
drive devices 116 may be suppressed. Further, since the dummy pads
119-1 to 119-6 are disposed in the first region 112a of the board
112 corresponding to a core 122b, heat generated from the light
emitting devices 114-1 to 114-n may be rapidly discharged to the
outside through the core 122b and thus heat dissipation efficiency
may be improved.
Further, for example, differently from FIG. 9, in accordance with
another embodiment, dummy pads may be disposed both in a first
region 112a of a board and in a region located between the first
and second regions 112a and 112b of the board 112. The reason for
this is to increase the size or area of the dummy pads so as to
further improve heat dissipation efficiency.
The dummy pads 119-1 to 119-6 may be formed of a material having
high thermal conductivity, for example, aluminum (Al), copper (Cu),
etc.
The dummy pads 119-1 to 119-6 may be connected to or contact a
conductive layer, pads, electrodes or lead frames provided on the
board 112 so as to mount the light emitting devices 114-1 to 114-n
thereon, but the disclosure is not limited thereto.
Otherwise, in accordance with another embodiment, the dummy pads
119-1 to 119-6 may be separated from a conductive layer, pads,
electrodes or lead frames provided on the board 112 so as to mount
the light emitting devices 114-1 to 114-n thereon.
For example, in order to suppress heat transfer to the drive
devices 116, the dummy pads 119-1 to 119-6 may be disposed to
surround the light emitting devices located in the outermost area
among the light emitting devices 114-1 to 114-n. Although FIG. 9
illustrates 6 dummy pads, without being limited thereto, the number
of the dummy pads may be 2 or more.
Further, in order to suppress heat transfer and to improve heat
dissipation efficiency, the area of the upper or lower surface of
each of the dummy pads 119-1 to 119-6 may be greater than the area
of a light emitting surface of each of the light emitting devices
114-1 to 114-n.
A third distance d3 between the dummy pads 119-1 to 119-6 and the
second region 112b may be 14 mm or more. The reason why the third
distance d3 is 14 mm or more is to prevent diffusion of heat to the
drive devices 116 by the dummy pads 119-1 to 119-6. For example,
the third distance d3 may be a distance between the dummy pads
119-1 to 119-6 and pads (not shown) of the board 112 on which the
drive devices 116 are mounted.
FIG. 10 is a table representing simulation results and test results
indicating temperatures of light emitting devices 114, temperatures
of condensers 116-3 and temperature differences .DELTA.T between
the light emitting devices 114 and the condensers 116-3 according
to change of diameters of cores.
Here, REF indicates temperature simulation results of an
illumination apparatus including a heat dissipation member not
provided with a core, and a board including a metal PCB. Here, a
condenser temperature may be the highest temperature out of
temperatures of the first and second condensers 116-3, and a
temperature difference .DELTA.T may be the smallest one out of a
temperature difference between the light emitting devices 114 and
the first condenser 116-3 and a temperature difference between the
light emitting devices 114 and the second condensers 116-3.
Case 1 is the case that the diameter D2 of a core 122b is 25 mm,
Case 2 is the case that the diameter D2 of the core 122b is 30 mm,
and Case 3 is the case that the diameter D2 of the core 122b is 40
mm.
In Case 1 to Case 3, a first part 130A of a housing 130 is an
aluminum mold casting formed integrally with a heat dissipation
member 120, a second part 130B of the housing 130 is formed of
plastic, a board 112 is a printed circuit board including FR4, the
diameter D1 of a first region 112a of the board 112 is 30 mm, the
heat dissipation member 120 is formed of aluminum, the thickness T1
of the core 122b is 5 mm, the thickness of heat dissipation fins
122c is 3 mm, the height of the heat dissipation fins 122c is 5 mm,
and the number of the heat dissipation fins 122c is 20. Cases 1 to
4 indicate simulation results.
With reference to FIG. 10, the condenser temperatures in Cases 1 to
3 are lower than the condenser temperature in REF in which no core
122b is provided. The condenser temperature in REF is 74.72.degree.
C.
If the diameter D2 of the core 122b is 25 mm, the condenser
temperature is 53.84.degree. C.
If the diameter D2 of the core 122b is 30 mm, the condenser
temperature is 53.85.degree. C.
If the diameter D2 of the core 122b is 40 mm, the condenser
temperature is 53.89.degree. C.
For example, in order to maintain a condenser temperature of less
than 54.degree. C., the diameter D2 of the core 122b may be 25 mm
to 40 mm.
A ratio (D2/D1) of the diameter D2 of the core 122b to the diameter
D1 of the first region 112a of the board 112 may be 5/7 to 8/5. For
example, D2/D1 may be 5/6 to 4/3.
For example, if D2/D1 is less than 5/6 or more than 4/3, the
condenser temperature may be 54.degree. C. or more and thus the
lifetime of the condensers 116-3 may be shortened by heat.
Case 4 represents temperature simulation results of an illumination
apparatus including the light emitting module 110-1 shown in FIG.
9, the distance between the dummy pads 119-1 to 119-6 and the
condensers 116-3 is 14 mm, the housing 130 is an aluminum mold
casting, the diameter D2 of the core 122b is 30 mm, the board 112
is a printed circuit board including FR4, the diameter D1 of the
first region 112a of the board 112 is 30 mm, the heat dissipation
member 120 is formed of aluminum, the thickness T1 of the core 122b
is 5 mm, the thickness of the heat dissipation fins 122c is 3 mm,
the height of the heat dissipation fins 122c is 5 mm, and the
number of the heat dissipation fins 122c is 20.
Since, in case 4, heat is dissipated by the dummy pads 119-1 to
119-66 disposed around the light emitting devices 114-1 to 114-n,
the condenser temperature is lowered, as compared to Case 1 to Case
3. That is, the condenser temperature of Case 4 is 48.38.degree. C.
which is lowered by about 5.degree. C., as compared to the
condenser temperature of Case 3. Therefore, the dummy pads 119-1 to
119-6 suppress transfer of heat generated from the light emitting
devices 114-1 to 114-n to the drive devices 116 and improves heat
dissipation efficiency, thereby preventing increase in the
temperature of the drive devices 116 and thus preventing damage to
the drive devices 116 due to heat.
Case 5 represents test results of Case 2, and FIG. 11 is a table
representing test results of Case 4 of FIG. 10.
Ts1 indicates a surface temperature of any one of the light
emitting devices 114-1 to 114-n, and Ts2 indicates a surface
temperature of another one of the light emitting devices 114-1 to
114-n.
L1 and L2 indicate temperatures of inductors, BR1 indicates a
temperature of the bridge diode 116-1, L3 coil indicates a
temperature of a coil of the voltage converter 116-2, L3 core
indicates a temperature of an iron core of the voltage converter
116-2, ZD1 indicates a temperature of the output diode, C9 and C10
indicate temperatures of the condensers 116-3, U1 indicates a
temperature of the driver IC, D/P indicates a temperature of the
diffusion plate 140, Tc1 indicates a temperature of the core 122b,
Tc2 indicates a temperature of the side surface of the housing 130,
and Q1 indicates a temperature of the FET.
When operating voltage is 120 V and power consumption is 10.86 W,
the surface temperature of the light emitting device 114 is
68.2.degree. C. and the temperature of the condenser 116-3 is
46.6.degree. C. Here, the surface temperature of the light emitting
device 114 may be the highest temperature out of the measured
temperatures of the light emitting devices 114-1 to 114-n.
Case 6 represents temperature simulation results of the
illumination apparatus 100 including the housing 130 formed of
plastic, shown in FIG. 1. The first part 130A and the second parts
130B of the housing are formed of plastic, the diameter D2 of the
core 122b is 30 mm, the board 112 is a printed circuit board
including FR4, the diameter D1 of the first region 112a of the
board 112 is 30 mm, the heat dissipation member 120 is formed of
aluminum, the thickness T1 of the core 122b is 5 mm, the thickness
of the heat dissipation fins 122c is 3 mm, the height of the heat
dissipation fins 122c is 5 mm, and the number of the heat
dissipation fins 122c is 20.
FIG. 12 is a table representing test results of Case 6 of FIG.
10.
With reference to FIG. 12, when operating voltage is 120 V and AC
power consumption of is 10.86 W, the surface temperature of the
light emitting device 114 is 77.5.degree. C. and the temperature of
the condenser 116-3 is 53.4.degree. C. As compared with Case 5, the
surface temperature of the light emitting device 114 of Case 6 is
raised by 9.3.degree. C. and the temperature of the condenser 116-3
of Case 6 is raised by 6.8.degree. C., but the temperature of the
condenser 116-3 of Case 6 is less than 54.degree. C. and thus
damage to the condenser 116-3 due to heat may be prevented and the
lifetime of the condenser 116-3 may be improved.
The lifetime of the drive devices 116 may be influenced by the
surface temperature of the drive devices 116 and a difference
between the surface temperature of the drive devices 116 and
ambient temperature around the illumination apparatus 100. If the
surface temperature of the drive devices 116 is high, the lifetime
of the drive devices 116 may be shortened. Particularly, the
condenser 116-3 is weak to heat and the lifetime thereof may thus
be shortened by heat received from the light emitting devices 114-1
to 114-n.
In Case 1 to Case 6, when the light emitting devices 114-1 to 114-n
emit light, the temperature of the drive devices 116, particularly,
the temperature of the condensers 116-3 may be maintained to be
lower than 54.degree. C. and thus the lifetime of the drive devices
116 may be improved.
Further, in Case 4 to Case 6, the temperature of the condensers
116-3 may be maintained to be lower than 80.degree. C. and thus the
lifetime of the drive devices 116 may be further improved.
As is apparent from the above description, an illumination
apparatus in accordance with one embodiment may prevent lifetime of
drive devices from being shortened due to heat generated from light
emitting devices.
Although embodiments have been described with reference to a number
of illustrative embodiments thereof, it should be understood that
numerous other modifications and embodiments can be devised by
those skilled in the art that will fall within the spirit and scope
of the principles of this disclosure. More particularly, various
variations and modifications are possible in the component parts
and/or arrangements of the subject combination arrangement within
the scope of the disclosure, the drawings and the appended claims.
In addition to variations and modifications in the component parts
and/or arrangements, alternative uses will also be apparent to
those skilled in the art.
* * * * *